The Firelands Invasion event
rewards items with a level of 365, as well as profession patterns for
crafting items of the same level.

New profession patterns drop from the Firelands drop from
the trash mobs in the Firelands. They enable crafting items with a level of
378.

Valor Quartermasters have had their rewards upgraded and now sell
items with a level of 378.

In both normal and heroic difficulty, trash mobs in the Firelands drop BoE
items with a level of 378.

In normal difficulty, raid bosses in the Firelands drop items (some are BoE)
with a level of 378. Items dropped by Ragnaros, the end boss, have a level of
384.

The Avengers of Hyjal faction (a sort of Ashen Verdict equivalent for the
Firelands) rewards items with a level of 378 (vendor is located just outside
the entrance of Firelands). More items become available
as your standing with that faction increases (presumably by killing raid bosses
in the Firelands).

In heroic difficulty, raid bosses in the Firelands drop items with a level
of 391 (397 for Ragnaros).

The Avengers of Hyjal enable you to replace some items with a level of
378 (all BoE items from the Firelands and some Valor Point rewards) by
their heroic (item level 391) version. To do so, you need to turn in,
at one of the two NPCs just outside of the Firelands,
the normal version of the item
plus a Crystallized Firestone (a token that drops in heroic difficulty
from raid bosses in the Firelands).

We felt that presenting the class sets together with the rest of the items
would have resulted in a cluttered listing. For this reason, we have decided
to present them separately.

2.1. Obtention System

As usually, the class sets are made up of 5 pieces: Head, Shoulders, Chest,
Hands, and Legs. There are 2 versions of the sets, a normal version
(item level 378) and a heroic version (item level 391). All pieces can be bought
from Valor Quartermasters, while some can
also drop from Occu'thar in Baradin Hold.

The pieces for the normal version can be obtained in the following ways: